Drill point thinning attachment



Oct. 3, 1950 A. VAN WYK DRILL POINT THINNING ATTACHMENT 2 Sheets-Sheet 1 Filed March 1, 1948 \NVENTOK ADRIAN VAN WYK Arm navs Patented Oct. 3, 1950 2,524,279 DRILL POINT THINNING ATTACHMENT Adrian Van Wyk, Grand Rapids, Mich., assignor to Gallmeyer & Livingston Company, Grand Rapids, Mich., a corporation of Michigan Application March 1, 1948, Serial No. 12,278

4 Claims.

This invention relates to a very practical, eflective, novel and useful attachment for thinning,

drill points, particularly drills of the twist drill, or similar, types and characters.

When a drill is new and of full length, the thickness of the drill at its point between the flutes has been properly measured and provided. Drills are subject to wear and grinding at their pointed ends and, therefore, a decrease in length. With such decrease in length, the distance through or thickness of the drill between the helical grooves progressively increases as such thickness is not uniform for the length of the drill between its point and the shank at which the helical grooves end. Accordingly, with continued sharpening and grinding of the drill at its pointed end and a progressive decrease in length, the thickness of the drill at the point progressively increases.

It is a primary object and purpose of the present invention to provide a very practical and effective attachment for grinding machines whereby the drill may be thinned at its pointed end and accurately ground at each side to reduce the thickness at and adjacent the point and to insure that the same amount shall be ground at each side of the longitudinal center axis of the drill.

The present invention not only insures that the thinned part of the drill at and adjacent its point shall be accurately provided with equal amounts at and adjacent the drill point to each side of the longitudinal axis of the drill, but the extent to which the grinding and thinning is made back of the point is accurately controlled. Furthermore, as drills of different diameter dimensions require different thicknesses at and adjacent the point, the present invention simply and practically places within the control of the operator the necessary adjustment for the attainment of such result. There are many other adjustmentsfor positioning the drill, as will appear.

An understanding of the invention may be had from the following description, taken in connection with the accompanying drawings, in which,

Fig. 1 is an elevation showing the drill point thinning attachment of my invention mounted in operative association with a grinding wheel,

Fig. 2 is a fragmentary front elevation with the drill holder removed and parts broken away and shown in section for disclosing the mechanism for movement of the drill point away from the grinding wheel,

Fig. 3 is a fragmentary enlarged plan and horizontal section illustrating the mechanism for lateral adjustment of the drill with respect to the grinding wheel with which it is associated,

Fig. 4 is a fragmentary plan view of the lateral adjusting means and the upper end portion of thedrill holder,

Fig. 5 is an end view of a drill after it has been processed on the machine, and

toward and a Fig. 6 is a fragmentary side elevation of the processed end of the drill.

Like reference characters refer to like parts in the different figures of the drawings.

A vertical pedestal support I has at the upper end and extending to" one side thereof a driven shaft 2, upon which a vertically positioned grinding wheel 3 is secured, covered by the usual protecting hood i, a portion of the wheel extending beyond the hood at what may be termed the front of the machine. The usual dressing implement 5 for dressing the periphery of the wheel is conventional and well known.

At the front side of the supporting pedestal I a bracket fixture 6 is bolted and receives one end portion of a cylindrical rod 1, which may be adjusted about its horizontal axis and clamped against turning movement by tightening the clamping screw of the split holding bracket 6, as shown in Fig. 1.

At its outer end the rod 1 is axially bored for a distance, at the outer end of which a nut 8 is secured, interiorly bored and threaded as shown in Fig. 3. A sleeve 9 surrounds the outer end portion of the rod 1 and a larger sleeve l0, longer than the sleeve 9 and longitudinally slotted from its inner end for part of its length at one side, surrounds said sleeve 9, extending outwardly beyond it and beyond the outer end of the rod 1. At its outer end it is closed by a closure I I, through which a shaft l2 passes and is rotatably mounted, the inner portion of which is threaded to screw through the nut 8. At its outer end it is equipped with a hand wheel 13 for manual turning. Thus the sleeve It may be adjusted in the direction of its length on the rod l and it also may be rocked back and forth about the longitudinal axis of the rod. At its inner end the sleeve I ll carries a ring it of flat metal secured thereto, through which the rod 1 passes and between which ring and the inner end of the sleeve 9 suitable packing is held. The sleeve Ill may be adjusted to different positions to which it is to be clamped upon the rod 1 and is turnable about suchrod, by a clamping screw i5 at the longitudinally slotted side of the outer sleeve I 0.

An arm or boss i9, integral with the outer sleeve ID (Fig. 1), extends upwardly and forwardly, upon which a drill holder to carry the drill which is to be ground, is mounted. The rocking of the sleeve Iii about the longitudinal axis of the rod I is limited in both directions. A stoparm I! extending from sleeve it comes at its end against an abutment 4a on the hood 4, limiting the turning movement of the sleeve i0 (Fig. 1) in a clockwise or outward direction. A screw 18 threaded through a lug 16a. extending to one side of the arm It at its inner end comes against a stop at l9' in fixed relation to the supporting pedestal. I, thus limiting the reverse rocking movement of the sleeve II] in an inward direction. It is apparent that by adjusting the screw 18 the extent or degree of rocking movement inwardly may be controlled and held to a preselected movement.

The arm [6 is axially bored and is split at-one side, with which a clamping screw provided with a handle 29 is associated for tightening the arm upon a rod 'or stem 2| of the drill holder or car rier. Said stem 2| at its-upper end. is connected "23 passes through the-head 22 and'ex't'endsdownwardly and forwardly'therefrom, the head 22 likewisebeingsplit at one side and provid'ed'with a clamping means 2a to clamp .against and hold the rod 23 against movement. 'The drill which is to be ground-and thinned at and adjacentits point .is carried .in two V-shaped carriers 25 and 26, thelatterbelowand outwardly of the former. Toward the lower end of the rod 23 a backing plate .27 for the end of the drill opposite its point is carried on a rod 28, slidable through a block 29 secured to the rod-23, and which may be held in anyposition to which it is moved through the block 29 by a set screw as shown. 7

At the upper inner end of one side of the upper V-shaped drill-carrier 25, a stop plate 30 is adjustaloly mounted, which has a free end bent inwardly and across the front upper end of the V-holder, against which one sidec-f a flute of a drill .31 which is to be ground is placed for posii tionin the drill. The drill remains in such position when the drillholder with the drill therein is lifted upwardly and moved-toward-the-grindingwheel 3 about the horizontal'axis of the rod 7.

-It is-f course apparent that the drill holder and the drill carried thereby, being connected with the sleeve l9,-m'ay be readily adjusted so as to bring the pointed upper end of'thedrill against the p'eriphery and a vertical side of-the grinding wheel 9-so 'as'to grind a flat surface at -32 at a side of the pointed end of the drill and-at a short distance to one side of the longitudinal'axis of the drill; The distanceeack that the'pointed'end of thedrillwillbeground at one side is controlled by the adjustment of the screw 18, the end of which coming against the stop at 19 stops the movement of the drill inwardly with reference to the grinding wheel 3. Then by turningthe drill over orthrough .a half circle :and bringing isn'anyiangl'es with reference to the grinding wheel and that differentdrills may be properly located and positioned. Any drill having a standard thickness at or closely adjacent the point when {-new, can be-maintained at such thickness by "thinning theprogressively increasingly thick center-of the drillas'it isworn off and reground at its end.

The-structure isvery practical and useful-and is p'artic'ularly desirable in properly thinning drills at their adjacent pointed ends as they are used up'in service.

The invention is defined in the appended claims and is to be considered comprehensive of all forms 'of' structure coming within their scope.

I claim:

1. .Ina machine of the class described, a grinding wheel mounted to turn about a horizontal axis and positioned vertically, a support adjacent said grinding wheel, a horizontal rod mounted on said support below and on an axis parallel to the axis of rotation of the grinding wheel, a sleeve rockably mounted on said rod, an

"arm "connected: with said sleeve extending upwardly towai'dthe adjacent edges of the grindln'g wheel, a drill holder carried bysaid arm extending outwai" ly'away from the grindin'g'wheel, said drilljholderhaving structure adapted to carry 3 a drill'jwith its pointed end adjacent the grinding fwhe'el, manually operable means for adjusting 'isaid sleeve lengthwise of said rod on which it'is 'carrie'd, adjustable means carried by said arm, a stop carried by said support against which said "adjustable means engages'on rocking the sleeve, "arm and drill'holder toward the grinding wheel, and a stopme'ans at the upper end of the drill "holder, against which a drill carried thereby is adapted "to engage 'at'opposite sides of the'drill .torjgrin'din said drill at and adjacent its point in planessubstantially parallel to each other, each located substantially equal distances from the longitudinal center line of .the drill.

'2. A.s'tructure' as defined in claim 1, said adjustabl'e rneanscarried by the'arm comprising, a

. 'ment of'said sleeve and drill holderin the move- "mem thereof toward the grinding wheel.

3. A structure as defined in claim 1, said means v for longitudinally adjusting said sleeve on said rod comprising, a nut fastened at the outer'end of said rod, said rod having a longitudinal axial borling'ifrom its outer end inwardly for a-distance, a closurefor the outer end of the sleeve, a rod extending through and rotatably mounted on said sleeve-havin a threaded inner end portion passing through said. nut, and manually engageable :means at the outer end of said threaded rec. for

' turningit.

4.-A.structure as defined in claim 1, said sleeve --beinglongitudinally slotted at one side, and means said sleeve.

adjustably connecting the sleeve at opposite sides of the slot therein-for contracting or releasing ADRIAN VAN WY K.

. REFlElitENCES CITED l he following references are of record-in the file of this patent:

UNITED STATES PATENTS "Fr'ance Apr. 12,1943 

